Features: 1. Pull The Switch To Choose To Output To The Radio Station Or Directly Make Sound. 2. 2xAAA Batteries Can Be Installed Inside To Push The Buzzer To Sound. 3. It Can Be Used For Beginners To Learn Or Perform. 4. CCTV10, Approaching Science, "Decoding The History Of Science And Technology", "Marconi And Radio", Uses This Key. 5. Manual CW Electric Keyboard With Built-In Buzzer For Teaching CW Electric Key Description: 1. Battery Type: 2xAAA(include) 2. Product Name: CW Key 3. Type: Morse Code Key 4. Function: CW Key Manual Morse Code size: 4.7 x 2.3cm Material: ABS+metal colour: black Package Contents: 4 x CW Electric Keys Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.